Download The respiratory system – structure and function

The respiratory system – structure and
function
• Every cell in our body needs a constant supply of oxygen
(O2) and food to maintain life and keep the body operating
effectively.
• The human respiratory system plays a significant role in
human movement. Whether it is short, sharp movements
over a limited period of time or repeated movements over
a long period of time, the human lungs will have a role to
play.
• The respiratory system supplies the blood with oxygen
through the breathing process. When humans breathe,
oxygen (O2) is inhaled and carbon dioxide (CO2) is exhaled.
This exchange of gases is the respiratory systems means of
getting O2 to the blood.
The human respiratory system
1. When we breathe in (inhale) O2 enters the respiratory
system through the mouth & nose.
2. The pharynx (throat) is the common passage for the air
to the trachea (windpipe) or food pipe (oesophagus). It
leads from the nasal cavity to the larynx (voice box).
3. The trachea is a hollow tube kept opened by rings of
cartilage. After entering the chest cavity (thorax) the
trachea divides into right and left bronchus which lead to
the right and left lungs.
4. The bronchus divides further into bronchial tubes
which divide into smaller tubes (bronchial) which connect
to tiny air sacs (alveoli). The inner lining of the air
passages produce mucus to catch and hold dirt and
germs. Microscopic hairs (cilia) remove dirt, irritants and
mucus through steady, rhythmic movements.
Cont.
5. There are 600+ million sponge-like alveoli whose with
very thin walls and this is where O2 exchange takes place.
Oxygen inhaled into the lung passes through the thin wall of
the alveoli and into the blood stream. At the same time
poisonous CO2 passes back into the lung through the wall of
the alveoli.
6. Control of the breathing action is done by the diaphragm
whose job is to help pump CO2 out of the lungs and create
space to allow the O2 to flow into the lungs.
The efficiency of the respiratory system has a big impact on
human performance. Those athletes who display highly
efficient lung function will often perform well in endurance
sports such as triathlon, soccer, ocean swimming.
Circulatory system
• What is the role of water in the circulatory
system (included with plasma)
• Water controls body heat through sweating. If
sweating is extreme excessive loss of water
from plasma and tissues can decrease blood
volume making frequent hydration
(replacement of water) necessary.